"Public opinion seems to achieve integration: the individuals trying to avoid isolation are ready to compromise, thereby furnishing society with some common ground which, as is generally acknowledged, is a condition for the society's survival. Public opinion seems to stabilize societies. Partly this is a consequence of integration but it is more. Political scientists interested in developing societies complain that the lack of public opinion, or of an infrastructure of consensus among persons interested in the political sphere, leads to extreme and frequent upheavals. Public opinion establishes priorities. In the field of communication research, this is called the agenda-setting function. It dictates what problems society deems to be its most urgent tasks. Public opinion confers legitimation. It is striving for consensus (exerting strong conformity pressure on the individuals), defending established norms, or creating those which in turn will be legally sanctioned. This is the meaning of 'all governments rest on opinion.'"
Noelle-Neumann, Elisabeth (1979). Public opinion and the classical tradition: A re-evaluation. Public Opinion Quarterly, 43(2), 143-156.